Also, these effector cells, such as CD8+ cytotoxic T cells, upregulate the expression of the PD-1 receptor, blocking the interaction with PD-L1 ligands, resulting in the inhibition of tumor growth and progression, so research exploring the balance of the tumor microdomain and these negative signals generated by PD-L1 is needed [18,19,20]. Here, CD8A is linked to neoplasm.